"Reasonably polarized"

Thoughts from philosopher Kevin Dorst (Oxford/Pittsburgh).  He writes: "The series will be the first pass at a book I've been working on for awhile, arguing that we should see polarization as due to largely rational processes. Basically, the claim is that we're all caught in a big epistemic tragedy of the commons where epistemically rational ways of processing ambiguous evidence lead to polarization."  One question I hope Professor Dorst will address is, if this is the explanation, why the epistemic tragedy of the commons is so much worse in the U.S. than many other affluent and nominally democratic nations.